Equipment For Producing Coils of a Stator of an Electrical Machine and Method For Making Coils

ABSTRACT

The invention relates to equipment for producing coils of a stator of an electrical machine and a method for producing coils. The coil is formed by connecting arms ( 6 ) of conducting pins ( 4 ) inserted into the slots ( 3 ) of a magnetic circuit ( 2 ) of the stator ( 1 ). The equipment comprises a shaper ( 10 ) axisymmetric about an axis ( 5 ), and the shaper ( 10 ) is designed to be placed inside the free ends of the arms ( 6 ) and in contact with the magnetic circuit ( 2 ). A series of guide-pins ( 12 ) equal in number to the slots ( 3 ) is designed so that each penetrates into a hole of the shaper ( 10 ). Each hole is drilled along an axis. The axes of the holes ( 13 ) meet at a first point ( 14 ) on the axis of revolution ( 5 ) of the shaper ( 10 ). Each guide-pin ( 12 ) is designed to separate two arms ( 6 ) of pins ( 4 ) inserted into two adjacent slots ( 3 ) to guide the arms ( 6 ) in a fixed direction, distinct from the direction of the arms ( 6 ) in their slot ( 3 ). The method using the previously described equipment includes successively carrying out the following operations. The pins ( 4 ) are inserted according to a wiring scheme for the coil; The first shaper ( 10 ) is put into place along the axis of revolution ( 5 ) of the magnetic circuit ( 2 ) on the free side of the arms ( 6 ) in contact with the magnetic circuit ( 2 ); The first series of guide-pins ( 12 ) are put into place. Each of the arms ( 6 ) is folded by pressing it onto a guide-pin ( 12 ) of the first series.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present Application is based on International Application No. PCT/EP2006/066939, filed on Sep. 29, 2006, which in turn corresponds to French Application No. 05 10019 filed on Sep. 30, 2005, and priority is hereby claimed under 35 USC §119 based on these applications. Each of these applications are hereby incorporated by reference in their entirety into the present application.

FIELD OF THE INVENTION

The invention relates to equipment for producing coils of a stator of an electrical machine and to a method for producing coils. The invention is of particular use in producing coils for high-power electrical machines.

BACKGROUND OF THE INVENTION

The coils consist of several windings. Each winding is formed by connecting conducting pins threaded into the slots of a magnetic circuit of the stator. The pins are produced from conductor bars, most often of rectangular section and made of a copper alloy. The bars are folded to form U-shaped pins. Consequently each branch of the U will be called an “arm”, and the central part of the U connecting the two arms will be called a “bend”. The free ends of the arms, that is the ends of the arms opposite the bend, are connected to each other according to a wiring scheme for the coil to form the windings. These connections form a lead-out wire to which the power supply leads for the windings are also connected. Each arm in the lead-out wire is folded so as to bring it closer to another arm to which it must be connected.

The operation of the electrical machine causes the stator to heat up due essentially to the flow of currents through the windings. An effective means of cooling the stator is to circulate a coolant therein, such as oil for example, that is circulated in the channels of the stator in immediate proximity of the pins. The lead-out wire hampers the circulation of the oil, principally due to the folds in the arms. In fact it is easy to fold the free ends of the arms immediately at the exit of the slots that they occupy. To provide a passage for oil between the arms in immediate proximity of the magnetic circuit, it is necessary in folding the arms to leave a part of the arm extended in continuation of the slot that it occupies before proceeding to the folding. This operation is particularly awkward to carry out manually, due notably to the elasticity of the material used to produce the pins.

SUMMARY OF THE INVENTION

The invention aims to overcome this problem by proposing equipment that simplifies the operation of folding the arms of the pins. This equipment guarantees a reproducible distance between the magnetic circuit and the folding of each arm. In a more general fashion, equipment conforming to the invention improves the reproducibility of the form of the lead-out wire and all the connections of the stator to be improved.

To this end, the subject of the invention is equipment for producing coils of a stator of an electrical machine, the coil comprising several windings, each winding being formed by connecting arms of conducting pins inserted into the slots of a magnetic circuit of the stator, characterized in that it comprises a shaper axisymmetric about an axis, the shaper being designed to be placed inside the free ends of the arms and in contact with the magnetic circuit, a first series of guide-pins equal in number to the slots and designed so that each penetrates into a hole of the shaper, each hole being drilled along an axis, the axes of the holes meeting at a first point on the axis of revolution of the shaper, each guide-pin being designed to separate two arms of pins inserted into two adjacent slots to guide the arms in a fixed direction, distinct from the direction of the arms in their slot.

The subject of the invention is also a method for producing coils of a stator of an electrical machine, the coil comprising several windings, each winding being formed by connecting arms of conducting pins threaded into the slots of a magnetic circuit of the stator, the method using the equipment of the invention, characterized in that it consists in successively carrying out the following operations:

-   -   inserting the pins into the slots according to a wiring scheme         for the coil;     -   putting the first shaper into place along the axis of revolution         of the magnetic circuit on the free side of the arms in contact         with the magnetic circuit;     -   putting the first series of guide-pins into place; and     -   folding each of the arms by pressing it onto a guide-pin.

Still other objects and advantages of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein the preferred embodiments of the invention are shown and described, simply by way of illustration of the best mode contemplated of carrying out the invention. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modifications in various obvious aspects, all without departing from the invention. Accordingly, the drawings and description thereof are to be regarded as illustrative in nature, and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWING

The present invention is illustrated by way of example, and not by limitation, in the figures of the accompanying drawings, wherein elements having the same reference numeral designations represent like elements throughout and wherein:

FIG. 1 shows equipment according to the invention set up for wiring a stator;

FIG. 2 shows a pin outside of its slot; and

FIG. 3 shows a partial section of two adjacent slots in a plane perpendicular to the axis of the stator.

For the sake of clarity the same elements have the same references in the different figures.

DETAILED DESCRIPTION OF THE DRAWING

FIG. 1 shows the stator 1 of an electrical machine. The stator 1 comprises a magnetic circuit 2 and a coil consisting of several windings. The magnetic circuit 2 is formed by a stack of laminations in which slots 3 are produced to receive the pins 4 which form the conducting elements of the coil. The magnetic circuit rotates about an axis 5. The laminations are planar and their plane is perpendicular to the axis 5, each winding being formed by connecting arms 6 of pins inserted into the slots 3. So as not to overload the figure, only some of the pins 4 are shown. A pin 4 is formed of two arms 6 linked by a bend 7. In FIG. 2 a pin 4 has been shown before being mounted in a slot 3. In general the slots 3 are filled by several bundles of pins 4. An example of how the slots 3 are filled is provided in FIG. 3. In FIGS. 1 and 3 two bundles have been shown. The various bundles can be separated by electrical insulators 8 and/or channels allowing a coolant, such as oil for example, serving to cool the stator in operation, to circulate. Electrical insulation 9 can surround all the elements, arms 6 and insulation 8, being located in a slot 3.

According to the invention, equipment for producing coils of the stator 1 comprise an axisymmetric shaper 10. The shaper is located inside the free ends 11 of arms 6 and in contact with the magnetic circuit 2. The axis of revolution of the shaper is coincident with the axis 5 of the magnetic circuit 2 and consequently has the same reference. The equipment furthermore comprises a first series of guide-pins 12 equal in number to the slots 3 and designed so that each penetrates into a hole 13 of the shaper 10. So as not to overload the figure, only one guide-pin 12 is shown. Each hole 13 is drilled along an axis, the axes of the holes 13 meeting at a first point 14 on the axis of revolution 5 of the shaper 10. Each guide-pin 12 is designed to separate two arms 6 threaded into two adjacent slots 3 to guide the arms 6 in a fixed direction, distinct from the direction of the arms 6 in their slot 3. In other words, once the guide-pins 12 are put into their respective hole 13, it is possible to fold the arm 6, which come to press against a guide-pin 12, to guide it in a direction different from that of the slot 3 it occupies. The shaper 10 is supported on the magnetic circuit 2, for example, by means of a shoulder 15 of the shaper 10 which comes to bear on an end lamination 16 of the magnetic circuit 2. The shaper 10 is, in addition, centered with respect to the magnetic circuit 2 by means of a cylindrical part 17 of the shaper 10 set into a bore 18 of the magnetic circuit 2. The bore 18 is, for example, used to put in place a rotor of the electrical machine, the rotor not being shown in FIG. 1.

Advantageously, the first point 14 is situated at a fixed, nonzero distance from the shoulder 15. This allows the arms 6 to be folded only from a certain distance from the end lamination 16 and therefore guarantees a reproducible distance between the magnetic circuit 2 and the folding of each arm 6. Maintaining the alignment of the arms 6 in their respective slots 3 allows the coolant to circulate better in the vicinity of the magnetic circuit 2, and more precisely along the end lamination 16.

The equipment also comprises two rings 20 and 21 constructed by means of bolts 22 and supporting the lamina of the magnetic circuit 2 during production of the coil.

Advantageously, the equipment comprises a second series of guide-pins 25, equal in number to the slots 3 and designed so that each penetrates into a hole 26 of the shaper 10. Each hole 26 is drilled along an axis. The axes of the holes 26 meet at a second point 27 on the axis of revolution 5 of the shaper 10. The point 27 is at a distance from the point 14. Each guide-pin 25 is designed to guide the arms 6 in a direction parallel to the direction of the arms 6 in their slot 3. As with the guide-pins 12, once the guide-pins 25 are put into their respective hole, it is possible to fold the arm 6, which ends up pressing against a guide-pin 25, in order to guide it in a direction parallel to that of the slot 3 it occupies.

Advantageously, the shaper 10 comprises a conical part 30 designed to move the arms 6 away from the axis 5 of the magnetic circuit 2. The conical part 30 comes into contact with the arms 6 when the shaper 10 is in contact with the magnetic circuit 2. The arms 6 thus follow the form of the conical part to move away from the axis 5. This provides the internal form of the lead-out wire.

Advantageously, the equipment comprises a second shaper 35, also axisymmetric. The second shaper 35 is designed to be placed inside the bends 7 and in contact with the magnetic circuit 2. The equipment also comprises a third series of guide-pins 36, equal in number to the slots 3 and designed so that each penetrates into a hole 37 of the second shaper 35. So as not to overload the figure, only one guide-pin 36 is shown. Each hole 37 is drilled along an axis, the axes of the holes 37 meeting at a point 38 on the axis of revolution 5 of the second shaper 35. Each guide-pin 36 is designed to separate two arms 6 threaded into two adjacent slots 3 so as to position the bends 7 at a fixed distance from the magnetic circuit 2. As with the shaper 10, the shaper 35 allows the arms 6 to be kept from being inserted totally into their respective slot and to preserve a straight part of the arms 6 outside of the slots 3. This allows the coolant to circulate better in the vicinity of the magnetic circuit 2, and more precisely along the end lamination 39 opposite the end lamination 16. In fact the pins 4 are preformed before being inserted in the slots 3. The longest part of the arms 6 is straight, a part designed to be inserted into the slots 3, and close to the bend 7, the arms 6 comprising folds 40. The position of the point 38 in relation to the end lamination 39 allows the folds 40 to be pressed against the third series of guide-pins 36. Using the guide-pins 36 makes it easier to produce the form of the lead-out wire containing the bends 7.

A method for producing coils using equipment as previously described consists in successively carrying out the following operations:

-   -   inserting the pins 4 into the slots 3 according to a wiring         scheme for the coil;     -   putting the first shaper 10 into place along the axis of         revolution 5 of the magnetic circuit 2 on the free side of the         arms 6 in contact with the magnetic circuit 2;     -   putting the first series of guide-pins 12 into place; and     -   folding each of the arms 6 by pressing it onto a guide-pin 12.

Before inserting the pins 4 into the slots 3, it is possible to insert insulating sleeves into the slots 3, into which sleeves the pins 4, where these are not insulated, are in turn inserted.

When several levels of arms 6 are inserted into the slots 3, as shown in FIG. 1, the various levels are generally folded with a different orientation. For example, folding is started at the level furthest from the axis 5 in a clockwise direction about the axis 5. Folding continues at a level closer to the axis 5 in a counterclockwise direction about the axis 5.

Advantageously, after having folded each of the arms 6 by pressing it onto a guide-pin 12 of the first series, the method consists in successively carrying out the following operations:

-   -   putting the second series of guide-pins 25 into place;     -   folding the arms 6 by pressing onto a guide-pin 25 of the second         series so as to guide the arms 6 in a direction parallel to the         direction of the arms 6 in their slots 3; and     -   connecting the arms 6 in accordance with a wiring scheme for the         coil.

This latter connection operation is carried out, for example, by means of rings inserted in two neighboring arms 6 at the free end, beyond the guide-pins 25. These rings are then brazed.

Advantageously, before the pins 4 have been inserted into the slots 3, the second shaper 35 pressing against the magnetic circuit 2 is put in place and the third series of guide-pins 36 is placed in the holes 37. Thus the folds 40 press against the guide-pins 36 to guarantee an identical distance between the bends 7 and the magnetic circuit 2. Supporting the folds 40 on the guide-pins 36 also allows a certain length of the straight part of the arms 4 to be kept out of the slots 3.

It will be readily seen by one of ordinary skill in the art that the present invention fulfils all of the objects set forth above. After reading the foregoing specification, one of ordinary skill in the art will be able to affect various changes, substitutions of equivalents and various aspects of the invention as broadly disclosed herein. It is therefore intended that the protection granted hereon be limited only by definition contained in the appended claims and equivalents thereof. 

1. Equipment for producing coils of a stator of an electrical machine, the coil having several windings, each winding being formed by connecting arms of conducting pins inserted into the slots of a magnetic circuit of the stator, comprising: a shaper axisymmetric about an axis, the shaper being designed to be placed inside free ends of the arms and in contact with the magnetic circuit, a first series of guide-pins equal in number to the slots and designed so that each penetrates into a hole of the shaper, each hole being drilled along an axis, the axes of the holes meeting at a first point on an axis of revolution of the shaper, each guide-pin being designed to separate two arms of pins inserted into two adjacent slots to guide the arms in a fixed direction, distinct from the direction of the arms in their slot.
 2. The equipment as claimed in claim 1, wherein the first point is situated a fixed distance from a bearing surface of the shaper on the magnetic circuit and wherein the fixed distance is nonzero.
 3. The equipment as claimed in claim 1, wherein it comprises a second series of guide-pins equal in number to the slots and designed so that each penetrates into a hole of the shaper, each hole being drilled along an axis, the axes of the holes meeting at a second point on the axis of revolution of the shaper, the second point being at a distance from the first point, each guide-pin of the second series being designed to guide the arms in a direction parallel to the direction of the arms in their slot.
 4. The equipment as claimed claim 1, the shaper comprising a conical part designed to move the arms of the pins away from an axis of the magnetic circuit.
 5. The equipment as claimed in claim 1, comprising a second shaper axisymmetric about an axis, the second shaper being designed to be placed inside the bends in the pins and in contact with the magnetic circuit, a third series of guide-pins equal in number to the slots and designed so that each penetrates into a hole of the second shaper, each hole being drilled along an axis, the axes of the holes meeting at a point on the axis of revolution of the second shaper, each guide-pin of the third series being designed to separate two arms of pins threaded into two adjacent slots so as to position the bends in the pin at a fixed distance from the magnetic circuit.
 6. A method for producing coils of a stator of an electrical machine, the coil comprising several windings, each winding being formed by connecting arms of conducting pins inserted into the slots of a magnetic circuit of the stator, the method using the equipment as claimed in claim 1, comprising successively carrying out the following operations: inserting the pins into the slots according to a wiring scheme for the coil; putting the first shaper into place along the axis of revolution of the magnetic circuit on the free side of the arms in contact with the magnetic circuit putting the first series of guide-pins into place; folding each of the arms by pressing it onto a guide-pin of the first series.
 7. The method as claimed in claim 6, using equipment for producing coils of a stator of an electrical machine, the coil having several windings, each winding being formed by connecting arms of conducting pins inserted into slots of a magnetic circuit of the stator, the equipment comprising: a shaper axisymmetric about an axis, the shaper being designed to be placed inside free ends of the arms and in contact with the magnetic circuit, a first series of guide-pins equal in number to the slots and designed so that each penetrates into a hole of the shaper, each hole being drilled along an axis, the axes of the holes meeting at first point on an axis of revolution of the shaper, each guide-pin being designed to separate two arms of pins inserted into two adjacent slots to guide the arms in a fixed direction, distinct from the direction of the arms in their slots, wherein the equipment comprises a second series of guide-pins equal in number to the slots and designed so that each penetrates into a hole of the shaper, each hole being drilled along an axis, the axes of the holes meeting at a second point on the axis of revolution of the shaper, the second point being at a distance from the first point, each guide-pin of the second series being designed to guide the arms in a direction parallel to the direction of the arms in their slot, wherein, after having folded each of the arms by pressing it onto a guide-pin of the first series, in successively carrying out the following operations: putting the second series of guide-pins into place; folding the arms by pressing onto a guide-pin of the second series so as to guide them in a direction parallel to the direction of the arms in their slots; and connect the arms in accordance with a wiring scheme for the coil.
 8. The method as claimed in claim 6, using a second shaper axisymmetric about an axis, the second shaper being designed to be placed inside the bends in the pins and in contact with the magnetic circuit, a third series of guide-pins equal in number to the slots and designed so that each penetrates into a hole of the second shapers each hole being drilled along an axis, the axes of the holes meeting at a point on the axis of revolution of the second shaper, each guide-pin of the third series being designed to separate two arms of pins threaded into two adjacent slots so as to position the bends in the pin at a fixed distance from the magnetic circuit, wherein, before inserting the pins into the slots, the second shaper is put in place pressing against the magnetic circuit and the third series of guide-pins is placed in the holes.
 9. The method as claimed in claim 7, using a second shaper axisymmetric about an axis, the second shaper being designed to be placed inside the bends in the pins and in contact with the magnetic circuit, a third series of guide-pins equal in number to the slots and designed so that each penetrates into a hole of the second shaper, each hole being drilled along an axis, the axes of the holes meeting at a point on the axis of revolution of the second shaper, each guide-pin of the third series being designed to separate two arms of pins threaded into two adjacent slots so as to position the bends in the pin at a fixed distance from the magnetic circuit wherein, before inserting the pins into the slots, the second shaper is put in place pressing against the magnetic circuit and the third series of guide-pins is placed in the holes. 